ANTINEOPLASTIC V LEUKEMOGENIC EPIPODOPHYLLOTOXIN EFFECTS

抗肿瘤 V 白血病表鬼臼毒素作用

• 批准号: 2756668
• 负责人: Carolyn A Felix
• 金额: $ 24.76万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-02-16 至 2002-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2756668
• 关键词: DNA topoisomerases; antineoplastics; blood chemistry; bone marrow; chromosome translocation; clinical research; cytochrome P450; drug adverse effect; drug carcinogenesis; drug metabolism; enzyme mechanism; etoposide; human subject; leukemia; molecular cloning; neoplasm /cancer genetics; podophyllin; polymerase chain reaction; urinalysis

DESCRIPTION: (Applicant's Abstract) The objective of this work is to better understand the mechanisms of epipodophyllotoxin-induced leukemogenesis. Epipodophyllotoxins result in treatment-related leukemias with translocations of the MLL gene at chromosome band 11q23. Current evidence suggests that both antineoplastic and leukemogenic epipodophyllotoxin effects are due to chromosomal breakage and that breakage resolved by chromosomal translocation is associated with leukemia. Epipodophyllotoxin parent compounds stabilize a DNA topoisomerase II-DNA covalent intermediate, decrease DNA topoisomerase II-mediated religation and cause chromosomal breakage. These events initiate an apoptotic cell death pathway, the desired antineoplastic action. Epipodophyllotoxins are metabolized to several compounds that may also lead to chromosomal breakage by creation of abasic sites or by forming DNA adducts. The applicant hypothesizes that epipodophyllotoxin as well as its metabolites may contribute to the breakage that results in translocations, and that secondary genetic changes, in addition to the translocations may also be required for leukemia to evolve. The first hypothesis is supported by new data that the genotype of cytochrome P-450 (CYP) 3A4, which metabolizes epipodophyllotoxin parent drug, may modulate the risk, while latency to the onset of disease suggests that there are secondary changes. In Aim 1 the applicant will clone MLL genomic translocation breakpoints by panhandle variant PCR and examine serial pre-leukemic and leukemic marrows to observe establishment of clonality by cells with a particular translocation. In Aim 2 the applicant will directly compare effects of etoposide and its metabolites on in vitro DNA topoisomerase II cleavage and religation at MLL genomic translocation breakpoints, and on breakage within the MLL gene in bone marrow stem cells. In Aim 3 the applicant will measure etoposide and potential leukemogenic metabolites in plasma and urine of patients undergoing treatment and concurrently examine chromosomal breakage in MLL and appearance of MLL gene translocations in the treated subjects. Using cDNA microarray technology, the applicant will appraise secondary genetic changes in treatment-related leukemias with MLL gene translocations in experiments of Aim 4. Successful execution of these Specific Aims will provide new knowledge of the etiology, pathogenesis, natural history and evolution of this treatment complication and may advance the rational design of leukemia preventive strategies that preserve the antineoplastic benefit of these important drugs.

描述：（申请人的摘要）这项工作的目的是 更好地了解表鬼臼毒素诱导的机制 白血病发生。表鬼臼毒素会导致治疗相关的 染色体带 11q23 处 MLL 基因易位的白血病。 目前的证据表明，抗肿瘤药物和致白血病药物 表鬼臼毒素的作用是由于染色体断裂造成的 通过染色体易位解决的断裂与 白血病。表鬼臼毒素母体化合物稳定 DNA 拓扑异构酶II-DNA共价中间体，降低DNA拓扑异构酶 II介导的重新连接并导致染色体断裂。这些事件 启动细胞凋亡途径，这是所需的抗肿瘤药物 行动。 表鬼臼毒素代谢为多种化合物，这些化合物也可能 通过产生脱碱基位点或形成 DNA 加合物。申请人假设表鬼臼毒素也 因为它的代谢物可能会导致断裂，从而导致 易位，以及继发性遗传变化，除了 白血病的进化也可能需要易位。第一个 新的数据支持了这一假设，即细胞色素的基因型 P-450 (CYP) 3A4 代谢表鬼臼毒素母药，可能 调节风险，而疾病发作的潜伏期表明 还有二次变化。在目标 1 中，申请人将克隆 MLL 通过 panhandle 变异 PCR 确定基因组易位断点并检查 连续白血病前期和白血病骨髓以观察建立 具有特定易位的细胞的克隆性。在目标 2 中 申请人将直接比较依托泊苷及其代谢物的效果 MLL 基因组的体外 DNA 拓扑异构酶 II 切割和再连接 易位断点以及骨骼中 MLL 基因内的断裂 骨髓干细胞。在目标 3 中，申请人将测量依托泊苷和 患者血浆和尿液中潜在的致白血病代谢物 接受治疗并同时检查染色体断裂情况 MLL 和接受治疗的受试者中 MLL 基因易位的出现。 利用cDNA微阵列技术，申请人将评估二级 MLL 基因治疗相关白血病的遗传变化 目标 4 实验中的易位。成功执行这些 具体目标将提供病因学、发病机制、 这种治疗并发症的自然史和演变，可能 推进白血病预防策略的合理设计 保留这些重要药物的抗肿瘤功效。